The timer is set at pcm reset and until it expires, the pcm can`t access mode 13. It is also reloaded at some point, maybe to prevent mode 13 at engine running.

I suspect it to be 8-10 seconds timout after reset is done, before you can access security mode. Rearmed on wrong key.

There are some other timers too. One of it is the time between seed response and key recieved. The purpose of the others is not so clear.